During the coming year, we plan to complete the characterization of the cobalt (III) complexes with the 2,2,3-tet ligand system in order to establish the degree of stereoselectivity imparted by this "backbone". A methyl substituted derivative, 3,6-diaza-8-methyl-l,9-nonanediamine will be prepared to determine if a methyl group placed on the six membered chelate ring imparts stereospecificity to chelation by this ligand. The synthesis of other unsymmetrical ligands, including those with three primary donors, will be explored (a key starting material was withdrawn from the market in 1975). We plan to complete the spectroscopic characterization (electronic and paramagnetic resonance spectra) of some tetrahedrally distorted copper (II) complexes, and from these studies to continue our synthetic efforts toward the joint goals of redox reversibility and spectroscopic properties which mimic "blue" proteins. We plan to measure reduction potentials for copper (II) complexes which are chemically reducible in order to explore the likelihood of participation by a copper-iron redox system in heme biosynthesis. We plan to continue our strain energy minimization project, extending the applications to tetrahedrally distorted copper (II) complexes.